Marks’ First Lessons in Geometry (1869) believed small children could reason geometrically long before they could parse Euclid — and set out to prove it. Bernhard Marks teaches entirely by diagram and oral question: pupils look, compare and conclude, with the printed text serving the teacher rather than the child.
It is an early landmark of object teaching in mathematics, and its method feels strikingly modern. Download the free EPUB and see geometry taught to eight-year-olds, 1869-style.